This proposal requests support funds for the First International Symposium on Hormonal Carcinogenesis to be held at the Hyatt Regency Cancun, Mexico, March 19-23-1991. It is intended that this will be the first in a series (every 3-4 years) of Symposia that will bring together a multidisciplinary group of participants to share their recent findings and current views on the evidently complex mechanism(s) involved in hormonal carcinogenesis. One of the unique features of this Symposium is that the proceedings will be published in a book, either chapter (oral presentations) or communications (poster presentations), by Springer-Verlag and will serve to focus attention on this very timely field and will allow for a wider dissemination of the most recent studies in this resurging area. Assembled for the scientific program are the most authoritive international investigators in the filed and it is anticipated they will provide for vigorous discussion and exchange. The following topics will be represented: 1) Carcinogenesis risk assessment of sex hormones (Pike, Lucier, Li, Isaacs); 2) Hormones, cell proliferation, and carcinogenesis (Gorski, Mauvais-Jarvis, Baldi, Beattie, Nandi); 3) Estrogen metabolism and carcinogenicity (Conney, Metzler, Siiteri, Guengerich, Li); 4) Hormones and tumor promotion (Lerner, Gustafsson, Yaeger, Ito, McLachlan); 5) Growth factors and oncogenes (Barrett, Groner, DiAugustine, Norris, Stancel); 6) Androgen/Progestin carcinogenesis (Bardin, Ho, Anderson, Charreau).